Maintaining profitability in agriculture
Changes in climate have and will continue to present challenges and opportunities for agricultural production in the Wimmera. The Wimmera farming community is renowned for its ability to innovate and adapt to its climate and market forces. This continual adaption and innovation has led to new crops and pastures, new varieties and changes to planting times and planting and management techniques. Many of these innovations are being driven by the agricultural industry and include plant breeding, chemical fertiliser development and machinery design.
Priorities for adapting to climate change for the Wimmera while maintaining profitability include:
- Maintaining research and development of plant breeding to cope with extreme and variable climatic conditions and to maximise benefits from increased atmospheric CO2 levels.
- Increased farm trials and research that test and demonstrate farm practices that allow farmers to adapt their practices to cope with climate extremes, for example: composting; crop and pasture breeding; new species of crops, pasture and fodder; crop cycles; planting time variations; controlled traffic farming; crop spacing, plant population; clay topping in appropriate areas to improve water retention and fertility and soil organic carbon.
- Farm planning.
- Make farming community aware of how to obtain and use the latest CSIRO and Bureau of Meteorology (BOM) climate predictions through the regional soil health agencies forum.
- Improved access to high quality weather seasonal forecasting.
- Increased engagement with Agribusiness.
- Potential impacts of climate change on cropping include:
- Potential increase in growth and yields as a result of increased atmospheric carbon dioxide.
- Without adaption, it is expected that increases in temperature could impact flowering and reduce grain yield which could counter the yield increase derived from higher levels of CO2.
- Potentially large reductions in rainfall could also reduce yields.
- Increases in CO2 could lead to reductions in grain nitrogen.
- Higher temperatures may lead to faster drying of grain which could reduce grain quality.
- Increased frequency of drought could reduce soil moisture and increase risk of crop failure.
Crop breeding and genetic modifications are potential solutions to these predicted impacts. Given limited funding there is a need to focus this effort into the most beneficial areas. Suggested crop breeding priorities may include:
- Maintaining varieties with similar or earlier flowering characteristics to allow grain fill in cooler wetter parts of the year.
- Drought tolerance.
- Flower retention.
- Grain protein.
- Disease and pest resistance.
- Heat shock resistance.
- Reduced dry down time.
- CO2 trait selection.
Methods such as growing crops all year round and under sowing promote carbon being fixed into the soils for a longer period. Under sowing is the sowing of a secondary crop underneath the primary cash crop. For instance, a cereal can be undersown with green feed or pasture species which should be well established by the time the cereal is harvested in mid to late summer. This can be considered as an adaptation and mitigation action as it can increase the storage of carbon and nitrogen (mitigation) and can also create a diversity of income from crops or pasture at various times of year (adaptation).
With climate change predictions suggesting lower winter rain and higher summer rain for the Wimmera, opportunities may emerge to grow two crops per annum. For example, growing a legume, followed by a cereal, one at a traditional time (April/May) and the other immediately after harvest when and if summer rainfall occurs or opportunistically during wet late spring. This may be limited to higher rainfall areas or where available soil moisture is present. Examples include sorghum, maize, and corn. There are other potential species grown in others areas of Australia that may become suitable in a changing climate.
- Support farmers to experiment with various crops and crop cycles across the Wimmera where this is based on good science.
- Investigate the opportunities and challenges of double cropping in the Wimmera.
Clay topping or claying is a practice that has been utilised in the Wimmera for about 20 years and is known to increase productivity and yields in some soil types. Sandy soils have low fertility levels due to low cationic exchange capacity (CEC) and low levels of organic carbon. Raising the clay content changes soil texture, which increases the capacity for the soil to store water and nutrients, increase cationic exchange capacity and soil organic carbon. Given this activity is somewhat focused on soil moisture retention this could impact on water availability for waterways if not managed correctly.
Claying trials are being conducted by a number of soil agencies, across the Wimmera, in a range of locations with different soils
types and rainfall.
- Develop and disseminate best practice information to landholders about clay topping in the Wimmera, to maximise profitability and minimise negative impacts, including waterway impacts.
The focus on this section is to address the potential impacts from climate change on soil and pasture rather than animal husbandry and emissions. For example it does not deal with the potential impacts on animals from heat stress or parasites.
CSIRO suggest that some of the potential impacts of climate change on grazing are:
- Declines in pasture productivity – as a result of changes in rainfall amounts and times.
- Reduced forage quality – as a result of changes in protein levels due to CO2 increases.
- Increased problems with pests, disease and weeds.
- More frequent and longer droughts.
- More intense rainfall events.
- Greater risk of soil erosion.
Community feedback has indicated that there is still much to learn and do to build the resilience of our grazing systems to cope with climate change. There are many theories about the potential impacts that the range of climate scenarios will have on grazing that require further investigation in real life situations.
C3 and C4 plants
Plants can be divided into different categories by the way in which they utilise carbon dioxide and their carbon fixation pathway and can be C3 or C4 or CAM (Crassulacean Acid metabolism) plants. Some research indicates C3 plants typically respond better to atmospheric CO2 enrichment than do C4 plants in terms of increasing their rates of photosynthesis and biomass
production. A warming climate is predicted to favour warm-season, or C4 grasses while rising CO2 should favour C3, or cool-season plants. Combined warming and CO2 enrichment stimulates above ground growth of C4 grasses most years when soil moisture most limits plant productivity.
There may be great opportunity for different C3, C4 or CAM pastures or fodder shrubs to be utilised as agricultural industries adapt to climate changes and the new and varied conditions. These plants may be annual or perennial and be grass, legume,
shrub or tree. More research and trials will need to occur to provide some certainty to land managers about the intricacies of
these theories and how pasture systems can be manipulated to deliver profitability.
Pasture breeding and genetic modification are potential solutions to the predicted impacts. Given limited funding there is a need to focus this effort into the most beneficial areas. The same logic for C3 and C4 plants can also be applied to weeds. Some weeds may become more vigorous meaning greater effort will be required for their control. Others may become climate stressed, providing an opportunity for greater control or eradication. This is discussed further in Section 2.5. The need for further research and trials has been highlighted as a high priority during stakeholder consultation.
Priority actions for research and trials for grazing include:
- The use of legumes and other nitrogen fixing plants in perennial pasture systems to improve nutrient cycling and ground cover.
- The economic benefits of perennial pasture/fodder systems in a range of soil types and rainfalls.
- Breeding opportunities in a broader range of species including: drought tolerance; summer dormancy of perennial pastures; plant persistence of perennial pastures; the challenges and benefits for pasture productivity and quality in real life situations from increases in CO2 levels; C3 and C4 plants and their benefits and challenges in a changing climate; the use of native grasses in a climate change environment in the Wimmera.
There was consensus, during stakeholder consultation, that landholders need to have access to information about practices
that can help them adapt their grazing systems to variations in the climate while remaining profitable. Priority extension activities include demonstrations and workshops on:
- Pasture management.
- Incorporation of legumes.
- New plant varieties.
- Sub-surface soil management.
There is also a need to deliver information through a range of mechanisms including, media, consultants and other landholders.